Even in the most lurid annals of British crime there has never been a player like Michael Michael. A lifetime of evil - including drug smuggling, money laundering and prostitution - brought him a fortune estimated at £107million. He ruled over his underworld domain like a feudal baron, respected and feted by the gangster elite.

However, it is not Michael's success as a villain that assures his place in criminal history; rather, it is his staggering capacity for betrayal.

On 25 April 1998, Customs investigators launched a "knock" codenamed Operation Draft. It uncovered 16kg of cocaine, 2.9 tons of cannabis worth £11.6 million, guns and £800,000 in cash. It also delivered up Michael Michael and 15 members of his gang. What happened next shocked even the Customs men and their police colleagues. Michael, an arch-criminal whose entire existence was founded on the underworld code, turned informer. So eager was he to name names, he is probably Britain's most prolific supergrass.

Not only did he inform on some of the most dangerous criminals operating today, he turned in his own mother, brother, wife, mistress and the madam who ran his brothels. And, it was to emerge, he had been "grassing up" his criminal colleagues for years. At his trial he accepted the suggestion he was a "polished liar" and offered the jury this explanation: "Yes, I had to lie, even to my family. It is in the business of informing and dealing ... being disloyal comes with the territory. My friends, family and lover are all awaiting trial because of me."

He named more than 60 criminals, ranging from millionaire master-villain Mickey Green to part-time drug mule Tracy Kirby, a former Page Three model. His information included names like Kenneth Noye, Ronnie Knight and Charlie Wilson and the details he revealed became a blueprint for a series of criminal prosecutions on a vast scale. In six completed trials, 34 defendants have been convicted and sentenced to terms ranging from 12 months to 21 years. Their sentences add up to 170 years.

Only now can Michael's story be told, because security considerations led to gagging orders and trials under armed guard at Woolwich Crown Court.

Michael, also known as Constantine, needed the security - underworld paymasters have put a £4 million price on his head. But he took a calculated risk when he decided to turn informer. When Customs raided his home in Radlett, Herts, he was carrying a gun, he had cash and other assets worth £1.6 million to hand, and he had accounts and contacts books detailing his drug and prostitution dealings.

It all added up to a prison sentence with little change out of 20 years. Even under that kind of pressure Michael cut an attractive deal. His wife Lynn, brother Xanthos and top lieutenant Janice Marlborough - all implicated by him - also turned Queen's Evidence.

The package Michael negotiated guarantees a new identity for himself and his immediate family, £19,000 a year for his wife to run a new home. £1,000 a month for their children's school fees, a £6,000 loan and £10,000 cash for a new car. His friends estimate that in all, he will benefit by around £2million from public funds, although even this does not compare with the fortune he was amassing from drugs and his massage parlour girls.

The girls operated in a chain of saunas run by Michael and his associates and earned him an estimated £500,000 a year. He was making even more out of drugs, which his gang brought into Britain from Holland, to be stored before sale in warehouses, mainly in the Hatfield area.

The couriers, who included his mother, wife, brother, and lover, never carried less than £250,000 each on every trip and in one 12-month period, 21 articulated lorries, three tourist coaches and numerous cars crossed the Channel laden with cannabis and cocaine. After the drugs were sold, the cash was delivered to Michael and either laundered through a bureau de change in Edgware, or changed into high denomination notes and sent back with couriers to Spain, Holland and France.

It took 250 interviews with Customs and police to unravel the information Michael offered. But despite the unparalleled scale of arrests and prosecutions that followed, the Michael Michael affair was not quite the triumph investigators had hope for.

A Customs source said: "We were very successful in catching and convicting people below Michael in the chain of command because we had corroborative evidence from documents and the accounts we seized when we arrested him.

"But when it came to those above him we only had his word for it. The opinion of Senior Treasury counsel was that we could not get convictions based solely on one man's word."

One man named by Michael was Mickey Green, the "Wembley Mob" armed robber turned drug dealer, wanted in four countries. Green was named as the man behind the gangland assassination of underworld figures Gilbert Wynter and Solly Nahome. Michael also accused Noel Purcell and Ian Davenport of being UK-based drug dealers.

He spoke of dealing with Spanishbased suppliers Clifford Wheeler and Stephen McGoldrick, described in court as "men of utmost violence". He named Cliff Hobbs who was said to have sent the drugs to Britain via France. But after six trials, just when it seemed these big players were about to face justice, the process came to an abrupt halt. Green was freed in June when charges were dropped.

In July, charges were dropped against McGoldrick. Detective Constable Paul Carpenter, on £50,000 bail and accused in court of being one of the most corrupt officers ever to serve in the Met, also had charges dropped.

Warrants have been issued for the arrest of Wheeler, Davenport and Hobbs but Customs say that now, after the end of Operation Draft, they are not "actively pursuing" them.

Michael's role as an informer is not over yet. He gave evidence, via a video link, in the Appeal Court earlier this month claiming that he was asked to act as the middleman in a £1million attempt to nobble the Guinness jury.

The Guinness four - Ernest Saunders, Gerald Ronson, Anthony Parnes and Sir Jack Lyons - were convicted in 1990 over an alleged fraudulent share support scheme in the takeover battle for Distillers in 1986.

Michael told the court he was approached by a "villain" known as Paul McGuire who told him he had a relative on the jury who was open to a bribe. Maguire had earlier told the court he had not spoken to Michael about a juror at all, to which the country's most prolific and bestrewarded supergrass replied: "He did."